---
title: "Prisma schema reference"
metaTitle: "Prisma Schema API"
metaDescription: "API reference documentation for the Prisma Schema Language (PSL)."
sidebar_label: "Prisma Schema"
tocDepth: 3
toc: true
---

## `datasource`

Defines a [data source](/orm/prisma-schema/overview/data-sources) in the Prisma schema.

### Fields

A `datasource` block accepts the following fields:

| Name                | Required | Type                                                                            | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| ------------------- | -------- | ------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `provider`          | **Yes**  | String (`postgresql`, `mysql`, `sqlite`, `sqlserver`, `mongodb`, `cockroachdb`) | Describes which data source connectors to use.                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| `url`               | **Yes**  | String (URL)                                                                    | **Deprecated in Prisma ORM v7.** Configure the connection URL in Prisma Config instead: see [`datasource.url`](/orm/reference/prisma-config-reference#datasourceurl). Existing schemas continue to work, but you should migrate to Prisma Config.                                                                                                                                                                                                                                                                     |
| `shadowDatabaseUrl` | No       | String (URL)                                                                    | **Deprecated in Prisma ORM v7.** Configure the shadow database URL in Prisma Config instead: see [`datasource.shadowDatabaseUrl`](/orm/reference/prisma-config-reference#datasourceshadowdatabaseurl).                                                                                                                                                                                                                                                                                                               |
| `directUrl`         | No       | String (URL)                                                                    | **Deprecated in Prisma ORM v7.** Configure the direct connection URL in Prisma Config instead: see [`datasource.directUrl`](/orm/reference/prisma-config-reference#datasourcedirecturl-removed).                                                                                                                                                                                                                                                                                                                             |
| `relationMode`      | No       | String (`foreignKeys`, `prisma`)                                                | Sets whether [referential integrity](/orm/prisma-schema/data-model/relations/relation-mode) is enforced by foreign keys in the database or emulated in the Prisma Client.<br /><br />In preview in versions 3.1.1 and later. The field is named `relationMode` in versions 4.5.0 and later, and was previously named `referentialIntegrity`.                                                                                                                                                                         |
| `extensions`        | No       | List of strings (PostgreSQL extension names)                                    | Allows you to [represent PostgreSQL extensions in your schema](/orm/prisma-schema/postgresql-extensions). Available in preview for PostgreSQL only in Prisma ORM versions 4.5.0 and later.                                                                                                                                                                                                                                                              |

::::note
As of Prisma ORM v7, the `url`, `directUrl`, and `shadowDatabaseUrl` fields in the Prisma schema `datasource` block are deprecated. Configure these fields in [Prisma Config](/orm/reference/prisma-config-reference) instead.
::::

The following providers are available:

- [`sqlite`](/orm/overview/databases/sqlite)
- [`postgresql`](/orm/overview/databases/postgresql)
- [`mysql`](/orm/overview/databases/mysql)
- [`sqlserver`](/orm/overview/databases/sql-server)
- [`mongodb`](/orm/overview/databases/mongodb)
- [`cockroachdb`](/orm/overview/databases/cockroachdb)

### Remarks

- You can only have **one** `datasource` block in a schema.
- `datasource db` is convention - however, you can give your data source any name - for example, `datasource mysql` or `datasource data`.

### Examples

#### Specify a PostgreSQL data source

In this example, the target database is available with the following credentials:

- User: `johndoe`
- Password: `mypassword`
- Host: `localhost`
- Port: `5432`
- Database name: `mydb`
- Schema name: `public`

```prisma
datasource db {
  provider = "postgresql"
  url      = "postgresql://johndoe:mypassword@localhost:5432/mydb?schema=public"
}
```

Learn more about PostgreSQL connection strings [here](/orm/overview/databases/postgresql).

#### Specify a PostgreSQL data source via an environment variable

In this example, the target database is available with the following credentials:

- User: `johndoe`
- Password: `mypassword`
- Host: `localhost`
- Port: `5432`
- Database name: `mydb`
- Schema name: `public`

```prisma
datasource db {
  provider = "postgresql"
}
```

When running a Prisma CLI command that needs the database connection URL (e.g. `prisma generate`), you need to make sure that the `DATABASE_URL` environment variable is set.

One way to do so is by creating a [`.env`](https://github.com/motdotla/dotenv) file with the following contents. Note that the file must be in the same directory as your `schema.prisma` file to automatically picked up the Prisma CLI.

```
DATABASE_URL=postgresql://johndoe:mypassword@localhost:5432/mydb?schema=public
```

#### Specify a MySQL data source

In this example, the target database is available with the following credentials:

- User: `johndoe`
- Password: `mypassword`
- Host: `localhost`
- Port: `3306`
- Database name: `mydb`

```prisma
datasource db {
  provider = "mysql"
  url      = "mysql://johndoe:mypassword@localhost:3306/mydb"
}
```

Learn more about MySQL connection strings [here](/orm/overview/databases/mysql).

#### Specify a MongoDB data source

- User: `root`
- Password: `password`
- Host: `cluster1.test1.mongodb.net`
- Port: N/A
- Database name: `testing`

```prisma
datasource db {
  provider = "mongodb"
  url      = "mongodb+srv://root:password@cluster1.test1.mongodb.net/testing?retryWrites=true&w=majority"
}
```

Learn more about MongoDB connection strings [here](/orm/overview/databases/mongodb).

#### Specify a SQLite data source

In this example, the target database is located in a file called `dev.db`:

```prisma
datasource db {
  provider = "sqlite"
  url      = "file:./dev.db"
}
```

Learn more about SQLite connection strings [here](/orm/overview/databases/sqlite).

#### Specify a CockroachDB data source

In this example, the target database is available with the following credentials:

- User: `johndoe`
- Password: `mypassword`
- Host: `localhost`
- Port: `26257`
- Database name: `mydb`
- Schema name: `public`

```prisma
datasource db {
  provider = "cockroachdb"
  url      = "postgresql://johndoe:mypassword@localhost:26257/mydb?schema=public"
}
```

The format for connection strings is the same as for PostgreSQL. Learn more about PostgreSQL connection strings [here](/orm/overview/databases/postgresql).

## `generator`

Defines a [generator](/orm/prisma-schema/overview/generators) in the Prisma schema.

### Fields for `prisma-client-js` provider

This is the default generator for Prisma ORM 6.x and earlier versions. Learn more about [generators](/orm/prisma-schema/overview/generators#prisma-client-js-deprecated).

A `generator` block accepts the following fields:

| Name              | Required | Type                                     | Description                                                                                                                                                                                                |
| :---------------- | :------- | :--------------------------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | 
| `provider`        | **Yes**  | `prisma-client-js`                       | Describes which [generator](/orm/prisma-schema/overview/generators) to use. This can point to a file that implements a generator or specify a built-in generator directly.                                 |
| `output`          | No       | String (file path)                       | Determines the location for the generated client, [learn more](/orm/prisma-client/setup-and-configuration/generating-prisma-client#using-a-custom-output-path). **Default**: `node_modules/.prisma/client` |
| `previewFeatures` | No       | List of Enums                            | Use intellisense to see list of currently available Preview features (`Ctrl+Space` in Visual Studio Code) **Default**: none                                                                                |    
| `engineType`      | No       | Enum (`library` or `binary`)             | Defines the [query engine](/orm/more/under-the-hood/engines) type to download and use. **Default**: `library`                                                                                              |
| `binaryTargets`   | No       | List of Enums (see below)                | Specify the OS on which the Prisma Client will run to ensure compatibility of the [query engine](/orm/more/under-the-hood/engines). **Default**: `native`                                                  |
| `moduleFormat`    | No       | Enum (`cjs` or `esm`)                           | Defines the module format of the generated Prisma Client. This field is available only with `prisma-client` generator.                                                                                                                         |

:::note[important]

We recommend defining a custom output path, adding the path to `.gitignore`, and then making sure to run `prisma generate` via a custom build script or postinstall hook.

:::

### Fields for `prisma-client` provider

The ESM-first client generator that offers greater control and flexibility across different JavaScript environments. It generates plain TypeScript code into a custom directory, providing full visibility over the generated code. Learn more about the new [`prisma-client`](/orm/prisma-schema/overview/generators#prisma-client) generator.

:::note

The `prisma-client` generator will be the default generator in Prisma ORM 7.0 and we recommend migrating to it as soon as possible. It has been Generally Available since [v6.16.0](https://pris.ly/release/6.16.0).

:::

A `generator` block accepts the following fields:

| Name                     | Required | Type                                                                                                                                        | Description                                                                                                                                                                                                                 |
| :----------------------- | :------- | :------------------------------------------------------------------------------------------------------------------------------------------ | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `provider`               | **Yes**  | `prisma-client`                                                                                                                            | Describes which [generator](/orm/prisma-schema/overview/generators) to use. This can point to a file that implements a generator or specify a built-in generator directly.                                                  |
| `output`                 | **Yes**  | String (file path)                                                                                                                          | Determines the location for the generated client, [learn more](/orm/prisma-client/setup-and-configuration/generating-prisma-client#using-a-custom-output-path).                                                             |
| `previewFeatures`        | No       | List of Enums                                                                                                                               | Use intellisense to see list of currently available Preview features (`Ctrl+Space` in Visual Studio Code) **Default**: none                                                                                                 |
| `runtime`                | No       | Enum (`nodejs`, `deno`, `bun`, `workerd` (alias `cloudflare`), `vercel-edge` (alias `edge-light`), `react-native`) | Target runtime environment. **Default**: `nodejs` |
| `moduleFormat`           | No       | Enum (`esm` or `cjs`)                                                                                                                       | Determines whether the generated code supports ESM (uses `import`) or CommonJS (uses `require(...)`) modules. We always recommend `esm` unless you have a good reason to use `cjs`. **Default**: Inferred from environment. |
| `generatedFileExtension` | No       | Enum (`ts` or `mts` or `cts`)                                                                                                               | File extension for generated TypeScript files. **Default**: `ts`                                                                                                                                                            |
| `importFileExtension`    | No       | Enum (`ts`,`mts`,`cts`,`js`,`mjs`,`cjs`, empty (for bare imports))                                                                          | File extension used in import statements **Default**: Inferred from environment.                                                                                                                                            |


#### `binaryTargets` options

The following tables list all supported operating systems with the name of platform to specify in [`binaryTargets`](/orm/prisma-schema/overview/generators#binary-targets).

Unless specified otherwise, the default supported CPU architecture is x86_64.

##### macOS

| Build OS           | Prisma engine build name |
| :----------------- | :----------------------- |
| macOS Intel x86_64 | `darwin`                 |
| macOS ARM64        | `darwin-arm64`           |

##### Windows

| Build OS | Prisma engine build name |
| :------- | :----------------------- |
| Windows  | `windows`                |

##### Linux (Alpine on x86_64 architectures)

| Build OS                | Prisma engine build name     | OpenSSL |
| :---------------------- | :--------------------------- | :-----: |
| Alpine (3.17 and newer) | `linux-musl-openssl-3.0.x`\* |  3.0.x  |
| Alpine (3.16 and older) | `linux-musl`                 |  1.1.x  |

\* Available in Prisma ORM versions 4.8.0 and later.

##### Linux (Alpine on ARM64 architectures)

| Build OS                | Prisma engine build name           | OpenSSL |
| :---------------------- | :--------------------------------- | :-----: |
| Alpine (3.17 and newer) | `linux-musl-arm64-openssl-3.0.x`\* |  3.0.x  |
| Alpine (3.16 and older) | `linux-musl-arm64-openssl-1.1.x`\* |  1.1.x  |

\* Available in Prisma ORM versions 4.10.0 and later.

##### Linux (Debian), x86_64

| Build OS             | Prisma engine build name | OpenSSL |
| :------------------- | :----------------------- | :-----: |
| Debian 8 (Jessie)    | `debian-openssl-1.0.x`   |  1.0.x  |
| Debian 9 (Stretch)   | `debian-openssl-1.1.x`   |  1.1.x  |
| Debian 10 (Buster)   | `debian-openssl-1.1.x`   |  1.1.x  |
| Debian 11 (Bullseye) | `debian-openssl-1.1.x`   |  1.1.x  |
| Debian 12 (Bookworm) | `debian-openssl-3.0.x`   |  3.0.x  |

##### Linux (Ubuntu), x86_64

| Build OS               | Prisma engine build name | OpenSSL |
| :--------------------- | :----------------------- | :-----: |
| Ubuntu 14.04 (trusty)  | `debian-openssl-1.0.x`   |  1.0.x  |
| Ubuntu 16.04 (xenial)  | `debian-openssl-1.0.x`   |  1.0.x  |
| Ubuntu 18.04 (bionic)  | `debian-openssl-1.1.x`   |  1.1.x  |
| Ubuntu 19.04 (disco)   | `debian-openssl-1.1.x`   |  1.1.x  |
| Ubuntu 20.04 (focal)   | `debian-openssl-1.1.x`   |  1.1.x  |
| Ubuntu 21.04 (hirsute) | `debian-openssl-1.1.x`   |  1.1.x  |
| Ubuntu 22.04 (jammy)   | `debian-openssl-3.0.x`   |  3.0.x  |
| Ubuntu 23.04 (lunar)   | `debian-openssl-3.0.x`   |  3.0.x  |

##### Linux (CentOS), x86_64

| Build OS | Prisma engine build name | OpenSSL |
| :------- | :----------------------- | :-----: |
| CentOS 7 | `rhel-openssl-1.0.x`     |  1.0.x  |
| CentOS 8 | `rhel-openssl-1.1.x`     |  1.1.x  |

##### Linux (Fedora), x86_64

| Build OS  | Prisma engine build name | OpenSSL |
| :-------- | :----------------------- | :-----: |
| Fedora 28 | `rhel-openssl-1.1.x`     |  1.1.x  |
| Fedora 29 | `rhel-openssl-1.1.x`     |  1.1.x  |
| Fedora 30 | `rhel-openssl-1.1.x`     |  1.1.x  |
| Fedora 36 | `rhel-openssl-3.0.x`     |  3.0.x  |
| Fedora 37 | `rhel-openssl-3.0.x`     |  3.0.x  |
| Fedora 38 | `rhel-openssl-3.0.x`     |  3.0.x  |

##### Linux (Linux Mint), x86_64

| Build OS      | Prisma engine build name | OpenSSL |
| :------------ | :----------------------- | :-----: |
| Linux Mint 18 | `debian-openssl-1.0.x`   |  1.0.x  |
| Linux Mint 19 | `debian-openssl-1.1.x`   |  1.1.x  |
| Linux Mint 20 | `debian-openssl-1.1.x`   |  1.1.x  |
| Linux Mint 21 | `debian-openssl-3.0.x`   |  3.0.x  |

##### Linux (Arch Linux), x86_64

| Build OS              | Prisma engine build name | OpenSSL |
| :-------------------- | :----------------------- | :-----: |
| Arch Linux 2019.09.01 | `debian-openssl-1.1.x`   |  1.1.x  |
| Arch Linux 2023.04.23 | `debian-openssl-3.0.x`   |  3.0.x  |

##### Linux ARM64 (all major distros but Alpine)

| Build OS                       | Prisma engine build name    | OpenSSL |
| :----------------------------- | :-------------------------- | :-----: |
| Linux ARM64 glibc-based distro | `linux-arm64-openssl-1.0.x` |  1.0.x  |
| Linux ARM64 glibc-based distro | `linux-arm64-openssl-1.1.x` |  1.1.x  |
| Linux ARM64 glibc-based distro | `linux-arm64-openssl-3.0.x` |  3.0.x  |

### Examples

#### Specify the `prisma-client-js` generator with the default `output`, `previewFeatures`, `engineType` and `binaryTargets`

```prisma
generator client {
  provider = "prisma-client-js"
}
```

Note that the above `generator` definition is **equivalent** to the following because it uses the default values for `output`, `engineType` and `binaryTargets` (and implicitly `previewFeatures`):

```prisma
generator client {
  provider      = "prisma-client-js"
  output        = "node_modules/.prisma/client"
  engineType    = "library"
  binaryTargets = ["native"]
}
```

#### Specify a custom `output` location for Prisma Client

This example shows how to define a custom `output` location of the generated asset to override the default one.

```prisma
generator client {
  provider = "prisma-client-js"
  output   = "../src/generated/client"
}
```

#### Specify custom `binaryTargets` to ensure compatibility with the OS

This example shows how to configure Prisma Client to run on `Ubuntu 19.04 (disco)` based on the table [above](#linux-ubuntu-x86_64).

```prisma
generator client {
  provider      = "prisma-client-js"
  binaryTargets = ["debian-openssl-1.1.x"]
}
```

#### Specify a `provider` pointing to some custom generator implementation

This example shows how to use a custom generator that's located in a directory called `my-generator`.

```prisma
generator client {
  provider = "./my-generator"
}
```

## `model`

Defines a Prisma [model](/orm/prisma-schema/data-model/models#defining-models) .

### Remarks

- Every record of a model must be _uniquely_ identifiable. You must define _at least_ one of the following attributes per model:
  - [`@unique`](#unique)
  - [`@@unique`](#unique-1)
  - [`@id`](#id)
  - [`@@id`](#id-1)

#### Naming conventions

- Model names must adhere to the following regular expression: `[A-Za-z][A-Za-z0-9_]*`
- Model names must start with a letter and are typically spelled in [PascalCase](https://wiki.c2.com/?PascalCase)
- Model names should use the singular form (for example, `User` instead of `user`, `users` or `Users`)
- Prisma ORM has a number of **reserved words** that are being used by Prisma ORM internally and therefore cannot be used as a model name. You can find the reserved words [here](https://github.com/prisma/prisma/blob/6.5.0/packages/client/src/generation/generateClient.ts#L556-L605) and [here](https://github.com/prisma/prisma-engines/blob/main/psl/parser-database/src/names/reserved_model_names.rs#L44).

> **Note**: You can use the [`@@map` attribute](#map-1) to map a model (for example, `User`) to a table with a different name that does not match model naming conventions (for example, `users`).

#### Order of fields

- In version 2.3.0 and later, introspection lists model fields in the same order as the corresponding columns in the database. Relation fields are listed after scalar fields.

### Examples

#### A model named `User` with two scalar fields

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email String  @unique // `email` can not be optional because it's the only unique field on the model
  name  String?
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id    String  @default(auto()) @map("_id") @db.ObjectId
  email String  @unique
  name  String?
}
```

</TabItem>
</TabbedContent>

## `model` fields

[Fields](/orm/prisma-schema/data-model/models#defining-fields) are properties of models.

### Remarks

#### Naming conventions

- Must start with a letter
- Typically spelled in camelCase
- Must adhere to the following regular expression: `[A-Za-z][A-Za-z0-9_]*`

> **Note**: You can use the [`@map` attribute](#map) to [map a field name to a column](/orm/prisma-client/setup-and-configuration/custom-model-and-field-names) with a different name that does not match field naming conventions: e.g. `myField @map("my_field")`.

## `model` field scalar types

The _data source connector_ determines what _native database type_ each of Prisma ORM scalar type maps to. Similarly, the _generator_ determines what _type in the target programming language_ each of these types map to.

Prisma models also have [model field types](/orm/prisma-schema/data-model/relations) that define relations between models.

### `String`

Variable length text.

#### Default type mappings

| Connector   | Default mapping  |
| ----------- | ---------------- |
| PostgreSQL  | `text`           |
| SQL Server  | `nvarchar(1000)` |
| MySQL       | `varchar(191)`   |
| MongoDB     | `String`         |
| SQLite      | `TEXT`           |
| CockroachDB | `STRING`         |

#### PostgreSQL

| Native database type | Native database type attribute | Notes                                                                                                                                                                    |
| :------------------- | :----------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `text`               | `@db.Text`                     |                                                                                                                                                                          |
| `char(x)`            | `@db.Char(x)`                  |
| `varchar(x)`         | `@db.VarChar(x)`               |
| `bit(x)`             | `@db.Bit(x)`                   |
| `varbit`             | `@db.VarBit`                   |
| `uuid`               | `@db.Uuid`                     |
| `xml`                | `@db.Xml`                      |
| `inet`               | `@db.Inet`                     |
| `citext`             | `@db.Citext`                   | Only available if [Citext extension is enabled](/orm/prisma-schema/data-model/unsupported-database-features#enable-postgresql-extensions-for-native-database-functions). |

#### MySQL

| Native database type | Native database type attribute |
| :------------------- | :----------------------------- |
| `VARCHAR(x)`         | `@db.VarChar(x)`               |
| `TEXT`               | `@db.Text`                     |
| `CHAR(x)`            | `@db.Char(x)`                  |
| `TINYTEXT`           | `@db.TinyText`                 |
| `MEDIUMTEXT`         | `@db.MediumText`               |
| `LONGTEXT`           | `@db.LongText`                 |

You can use Prisma Migrate to map `@db.Bit(1)` to `String`:

```prisma
model Model {
  /* ... */
  myField String @db.Bit(1)
}
```

#### MongoDB

`String`

| Native database type attribute | Notes                                                                             |
| :----------------------------- | :-------------------------------------------------------------------------------- |
| `@db.String`                   |                                                                                   |
| `@db.ObjectId`                 | Required if the underlying BSON type is `OBJECT_ID` (ID fields, relation scalars) |

#### Microsoft SQL Server

| Native database type | Native database type attribute |
| :------------------- | :----------------------------- |
| `char(x)`            | `@db.Char(x)`                  |
| `nchar(x)`           | `@db.NChar(x)`                 |
| `varchar(x)`         | `@db.VarChar(x)`               |
| `nvarchar(x)`        | `@db.NVarChar(x)`              |
| `text`               | `@db.Text`                     |
| `ntext`              | `@db.NText`                    |
| `xml`                | `@db.Xml`                      |
| `uniqueidentifier`   | `@db.UniqueIdentifier`         |

#### SQLite

`TEXT`

#### CockroachDB

| Native database type                     | Native database type attribute | Notes |
| :--------------------------------------- | :----------------------------- | ----- |
| `STRING(x)` \| `TEXT(x)` \| `VARCHAR(x)` | `@db.String(x)`                |       |
| `CHAR(x)`                                | `@db.Char(x)`                  |       |
| `"char"`                                 | `@db.CatalogSingleChar`        |       |
| `BIT(x)`                                 | `@db.Bit(x)`                   |       |
| `VARBIT`                                 | `@db.VarBit`                   |       |
| `UUID`                                   | `@db.Uuid`                     |       |
| `INET`                                   | `@db.Inet`                     |       |

Note that the `xml` and `citext` types supported in PostgreSQL are not currently supported in CockroachDB.

#### Clients

| Prisma Client JS |
| ---------------- |
| `string`         |

### `Boolean`

True or false value.

#### Default type mappings

| Connector   | Default mapping |
| ----------- | --------------- |
| PostgreSQL  | `boolean`       |
| SQL Server  | `bit`           |
| MySQL       | `TINYINT(1)`    |
| MongoDB     | `Bool`          |
| SQLite      | `INTEGER`       |
| CockroachDB | `BOOL`          |

#### PostgreSQL

| Native database types | Native database type attribute | Notes |
| :-------------------- | :----------------------------- | ----- |
| `boolean`             | `@db.Boolean`                  |       |

#### MySQL

| Native database types | Native database type attribute | Notes                                                                                                                                                     |
| --------------------- | ------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `TINYINT(1)`          | `@db.TinyInt(1)`               | `TINYINT` maps to `Int` if the max length is greater than 1 (for example, `TINYINT(2)`) _or_ the default value is anything other than `1`, `0`, or `NULL` |
| `BIT(1)`              | `@db.Bit`                      |

#### MongoDB

`Bool`

#### Microsoft SQL Server

| Native database types | Native database type attribute | Notes |
| :-------------------- | :----------------------------- | ----- |
| `bit`                 | `@db.Bit`                      |       |

#### SQLite

`INTEGER`

#### CockroachDB

| Native database types | Native database type attribute | Notes |
| :-------------------- | :----------------------------- | ----- |
| `BOOL`                | `@db.Bool`                     |       |

#### Clients

| Prisma Client JS |
| ---------------- |
| `boolean`        |

### `Int`

#### Default type mappings

| Connector   | Default mapping |
| ----------- | --------------- |
| PostgreSQL  | `integer`       |
| SQL Server  | `int`           |
| MySQL       | `INT`           |
| MongoDB     | `Int`           |
| SQLite      | `INTEGER`       |
| CockroachDB | `INT`           |

#### PostgreSQL

| Native database types      | Native database type attribute           | Notes |
| -------------------------- | ---------------------------------------- | ----- |
| `integer` \| `int`, `int4` | `@db.Integer`                            |       |
| `smallint` \| `int2`       | `@db.SmallInt`                           |       |
| `smallserial` \| `serial2` | `@db.SmallInt @default(autoincrement())` |       |
| `serial` \| `serial4`      | `@db.Int @default(autoincrement())`      |       |
| `oid`                      | `@db.Oid`                                |       |

#### MySQL

| Native database types | Native database type attribute | Notes                                                                                                                                                                                      |
| :-------------------- | :----------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `INT`                 | `@db.Int`                      |                                                                                                                                                                                            |
| `INT UNSIGNED`        | `@db.UnsignedInt`              |                                                                                                                                                                                            |
| `SMALLINT`            | `@db.SmallInt`                 |
| `SMALLINT UNSIGNED`   | `@db.UnsignedSmallInt`         |
| `MEDIUMINT`           | `@db.MediumInt`                |
| `MEDIUMINT UNSIGNED`  | `@db.UnsignedMediumInt`        |
| `TINYINT`             | `@db.TinyInt`                  | `TINYINT` maps to `Int` if the max length is greater than 1 (for example, `TINYINT(2)`) _or_ the default value is anything other than `1`, `0`, or `NULL`. `TINYINT(1)` maps to `Boolean`. |
| `TINYINT UNSIGNED`    | `@db.UnsignedTinyInt`          | `TINYINT(1) UNSIGNED` maps to `Int`, not `Boolean`                                                                                                                                         |
| `YEAR`                | `@db.Year`                     |

#### MongoDB

`Int`

| Native database type attribute | Notes |
| :----------------------------- | :---- |
| `@db.Int`                      |       |
| `@db.Long`                     |       |

#### Microsoft SQL Server

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `int`                 | `@db.Int`                      |       |
| `smallint`            | `@db.SmallInt`                 |       |
| `tinyint`             | `@db.TinyInt`                  |       |
| `bit`                 | `@db.Bit`                      |

#### SQLite

`INTEGER`

#### CockroachDB

| Native database types        | Native database type attribute       | Notes                                                                                                             |
| ---------------------------- | ------------------------------------ | ----------------------------------------------------------------------------------------------------------------- |
| `INTEGER` \| `INT` \| `INT8` | `@db.Int8`                           | Note that this differs from PostgreSQL, where `integer` and `int` are aliases for `int4` and map to `@db.Integer` |
| `INT4`                       | `@db.Int4`                           |                                                                                                                   |
| `INT2` \| `SMALLINT`         | `@db.Int2`                           |                                                                                                                   |
| `SMALLSERIAL` \| `SERIAL2`   | `@db.Int2 @default(autoincrement())` |                                                                                                                   |
| `SERIAL` \| `SERIAL4`        | `@db.Int4 @default(autoincrement())` |                                                                                                                   |
| `SERIAL8` \| `BIGSERIAL`     | `@db.Int8 @default(autoincrement())` |                                                                                                                   |

#### Clients

| Prisma Client JS |
| ---------------- |
| `number`         |

### `BigInt`

`BigInt` is available in version [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and later.

#### Default type mappings

| Connector   | Default mapping |
| ----------- | --------------- |
| PostgreSQL  | `bigint`        |
| SQL Server  | `int`           |
| MySQL       | `BIGINT`        |
| MongoDB     | `Long`          |
| SQLite      | `INTEGER`       |
| CockroachDB | `INTEGER`       |

#### PostgreSQL

| Native database types    | Native database type attribute         | Notes |
| ------------------------ | -------------------------------------- | ----- |
| `bigint` \| `int8`       | `@db.BigInt`                           |       |
| `bigserial` \| `serial8` | `@db.BigInt @default(autoincrement())` |       |

#### MySQL

| Native database types | Native database type attribute                 | Notes |
| --------------------- | ---------------------------------------------- | ----- |
| `BIGINT`              | `@db.BigInt`                                   |       |
| `SERIAL`              | `@db.UnsignedBigInt @default(autoincrement())` |       |

#### MongoDB

`Long`

#### Microsoft SQL Server

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `bigint`              | `@db.BigInt`                   |       |

#### SQLite

`INTEGER`

#### CockroachDB

| Native database types       | Native database type attribute       | Notes                                                                      |
| --------------------------- | ------------------------------------ | -------------------------------------------------------------------------- |
| `BIGINT` \| `INT` \| `INT8` | `@db.Int8`                           | Note that this differs from PostgreSQL, where `int` is an alias for `int4` |
| `bigserial` \| `serial8`    | `@db.Int8 @default(autoincrement())` |                                                                            |

#### Clients

| Client           | Type                                                                                                | Description                                                                                              |
| :--------------- | :-------------------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------- |
| Prisma Client JS | [`BigInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt) | See [examples of working with `BigInt`](/orm/prisma-client/special-fields-and-types#working-with-bigint) |

### `Float`

Floating point number.

> `Float` maps to `Double` in [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and later - see [release notes](https://github.com/prisma/prisma/releases/tag/2.17.0) and [Video: Changes to the default mapping of Float in Prisma ORM 2.17.0](https://www.youtube.com/watch?v=OsuGP_xNHco&amp%3Bab_channel=Prisma) for more information about this change.

#### Default type mappings

| Connector   | Default mapping    |
| ----------- | ------------------ |
| PostgreSQL  | `double precision` |
| SQL Server  | `float(53)`        |
| MySQL       | `DOUBLE`           |
| MongoDB     | `Double`           |
| SQLite      | `REAL`             |
| CockroachDB | `DOUBLE PRECISION` |

#### PostgreSQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `double precision`    | `@db.DoublePrecision`          |       |
| `real`                | `@db.Real`                     |       |

#### MySQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `FLOAT`               | `@db.Float`                    |
| `DOUBLE`              | `@db.Double`                   |

#### MongoDB

`Double`

#### Microsoft SQL Server

| Native database types | Native database type attribute |
| --------------------- | ------------------------------ |
| `float`               | `@db.Float`                    |
| `money`               | `@db.Money`                    |
| `smallmoney`          | `@db.SmallMoney`               |
| `real`                | `@db.Real`                     |

#### SQLite connector

`REAL`

#### CockroachDB

| Native database types          | Native database type attribute | Notes |
| ------------------------------ | ------------------------------ | ----- |
| `DOUBLE PRECISION` \| `FLOAT8` | `@db.Float8`                   |       |
| `REAL` \| `FLOAT4` \| `FLOAT`  | `@db.Float4`                   |       |

#### Clients

| Prisma Client JS |
| ---------------- |
| `number`         |

### `Decimal`

#### Default type mappings

| Connector   | Default mapping                                                |
| ----------- | -------------------------------------------------------------- |
| PostgreSQL  | `decimal(65,30)`                                               |
| SQL Server  | `decimal(32,16)`                                               |
| MySQL       | `DECIMAL(65,30)`                                               |
| MongoDB     | [Not supported](https://github.com/prisma/prisma/issues/12637) |
| SQLite      | `DECIMAL`                                                      |
| CockroachDB | `DECIMAL`                                                      |

#### PostgreSQL

| Native database types  | Native database type attribute | Notes |
| ---------------------- | ------------------------------ | ----- |
| `decimal` \| `numeric` | `@db.Decimal(p, s)`†           |       |
| `money`                | `@db.Money`                    |       |

- † `p` (precision), the maximum total number of decimal digits to be stored. `s` (scale), the number of decimal digits that are stored to the right of the decimal point.

#### MySQL

| Native database types  | Native database type attribute | Notes |
| ---------------------- | ------------------------------ | ----- |
| `DECIMAL` \| `NUMERIC` | `@db.Decimal(p, s)`†           |       |

- † `p` (precision), the maximum total number of decimal digits to be stored. `s` (scale), the number of decimal digits that are stored to the right of the decimal point.

#### MongoDB

[Not supported](https://github.com/prisma/prisma/issues/12637).

#### Microsoft SQL Server

| Native database types  | Native database type attribute | Notes |
| ---------------------- | ------------------------------ | ----- |
| `decimal` \| `numeric` | `@db.Decimal(p, s)`†           |       |

- † `p` (precision), the maximum total number of decimal digits to be stored. `s` (scale), the number of decimal digits that are stored to the right of the decimal point.

#### SQLite

`DECIMAL` (changed from `REAL` in 2.17.0)

#### CockroachDB

| Native database types           | Native database type attribute | Notes                                                         |
| ------------------------------- | ------------------------------ | ------------------------------------------------------------- |
| `DECIMAL` \| `DEC` \| `NUMERIC` | `@db.Decimal(p, s)`†           |                                                               |
| `money`                         | Not yet                        | PostgreSQL's `money` type is not yet supported by CockroachDB |

- † `p` (precision), the maximum total number of decimal digits to be stored. `s` (scale), the number of decimal digits that are stored to the right of the decimal point.

#### Clients

| Client           | Type                                               | Description                                                                                                |
| :--------------- | :------------------------------------------------- | :--------------------------------------------------------------------------------------------------------- |
| Prisma Client JS | [`Decimal`](https://mikemcl.github.io/decimal.js/) | See [examples of working with `Decimal`](/orm/prisma-client/special-fields-and-types#working-with-decimal) |

### `DateTime`

#### Remarks

- Prisma Client returns all `DateTime` as native [`Date`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date) objects.
- Currently, Prisma ORM [does not support](https://github.com/prisma/prisma/issues/5006) [zero dates](https://dev.mysql.com/doc/refman/8.3/en/date-and-time-types.html#:~:text=The%20following%20table%20shows%20the%20format%20of%20the%20%E2%80%9Czero%E2%80%9D%20value%20for%20each%20type) (`0000-00-00 00:00:00`, `0000-00-00`, `00:00:00`) in MySQL.
- There currently is a [bug](https://github.com/prisma/prisma/issues/9516) that doesn't allow you to pass in `DateTime` values as strings and produces a runtime error when you do. `DateTime` values need to be passed as [`Date`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date) objects (i.e. `new Date('2024-12-04')` instead of `'2024-12-04'`).

You can find more info and examples in this section: [Working with `DateTime`](/orm/prisma-client/special-fields-and-types#working-with-datetime).

#### Default type mappings

| Connector   | Default mapping |
| ----------- | --------------- |
| PostgreSQL  | `timestamp(3)`  |
| SQL Server  | `datetime2`     |
| MySQL       | `DATETIME(3)`   |
| MongoDB     | `Timestamp`     |
| SQLite      | `NUMERIC`       |
| CockroachDB | `TIMESTAMP`     |

#### PostgreSQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `timestamp(x)`        | `@db.Timestamp(x)`             |       |
| `timestamptz(x)`      | `@db.Timestamptz(x)`           |       |
| `date`                | `@db.Date`                     |       |
| `time(x)`             | `@db.Time(x)`                  |       |
| `timetz(x)`           | `@db.Timetz(x)`                |       |

#### MySQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `DATETIME(x)`         | `@db.DateTime(x)`              |       |
| `DATE(x)`             | `@db.Date(x)`                  |
| `TIME(x)`             | `@db.Time(x)`                  |
| `TIMESTAMP(x)`        | `@db.Timestamp(x)`             |

You can also use MySQL's `YEAR` type with `Int`:

```prisma
yearField     Int    @db.Year
```

#### MongoDB

`Timestamp`

#### Microsoft SQL Server

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `date`                | `@db.Date`                     |
| `time`                | `@db.Time`                     |
| `datetime`            | `@db.DateTime`                 |
| `datetime2`           | `@db.DateTime2`                |       |
| `smalldatetime`       | `@db.SmallDateTime`            |
| `datetimeoffset`      | `@db.DateTimeOffset`           |

#### SQLite

`NUMERIC` or `STRING`. If the underlying data type is `STRING`, you must use one of the following formats:

- [RFC 3339](https://www.ietf.org/rfc/rfc3339.txt) (`1996-12-19T16:39:57-08:00`)
- [RFC 2822](https://datatracker.ietf.org/doc/html/rfc2822#section-3.3) (`Tue, 1 Jul 2003 10:52:37 +0200`)

#### CockroachDB

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `TIMESTAMP(x)`        | `@db.Timestamp(x)`             |       |
| `TIMESTAMPTZ(x)`      | `@db.Timestamptz(x)`           |       |
| `DATE`                | `@db.Date`                     |       |
| `TIME(x)`             | `@db.Time(x)`                  |       |
| `TIMETZ(x)`           | `@db.Timetz(x)`                |       |

#### Clients

| Prisma Client JS |
| ---------------- |
| `Date`           |

### `Json`

A JSON object.

#### Default type mappings

| Connector   | Default mapping                                                                                              |
| ----------- | ------------------------------------------------------------------------------------------------------------ |
| PostgreSQL  | `jsonb`                                                                                                      |
| SQL Server  | [Not supported](https://github.com/prisma/prisma/issues/7417)                                                |
| MySQL       | `JSON`                                                                                                       |
| MongoDB     | [A valid `BSON` object (Relaxed mode)](https://www.mongodb.com/docs/manual/reference/mongodb-extended-json/) |
| SQLite      | `JSONB`                                                                                                      |
| CockroachDB | `JSONB`                                                                                                      |

#### PostgreSQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `json`                | `@db.Json`                     |
| `jsonb`               | `@db.JsonB`                    |       |

#### MySQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `JSON`                | `@db.Json`                     |

#### MongoDB

[A valid `BSON` object (Relaxed mode)](https://www.mongodb.com/docs/manual/reference/mongodb-extended-json/)

#### Microsoft SQL Server

Microsoft SQL Server does not have a specific data type for JSON. However, there are a number of [built-in functions for reading and modifying JSON](https://learn.microsoft.com/en-us/sql/relational-databases/json/json-data-sql-server?view=sql-server-ver15#extract-values-from-json-text-and-use-them-in-queries).

#### SQLite

Not supported

#### CockroachDB

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `JSON` \| `JSONB`     | `@db.JsonB`                    |       |

#### Clients

| Prisma Client JS |
| ---------------- |
| `object`         |

### `Bytes`

`Bytes` is available in version [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and later.

#### Default type mappings

| Connector   | Default mapping |
| ----------- | --------------- |
| PostgreSQL  | `bytea`         |
| SQL Server  | `varbinary`     |
| MySQL       | `LONGBLOB`      |
| MongoDB     | `BinData`       |
| SQLite      | `BLOB`          |
| CockroachDB | `BYTES`         |

#### PostgreSQL

| Native database types | Native database type attribute |
| --------------------- | ------------------------------ |
| `bytea`               | `@db.ByteA`                    |

#### MySQL

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `LONGBLOB`            | `@db.LongBlob`                 |       |
| `BINARY`              | `@db.Binary`                   |
| `VARBINARY`           | `@db.VarBinary`                |
| `TINYBLOB`            | `@db.TinyBlob`                 |
| `BLOB`                | `@db.Blob`                     |
| `MEDIUMBLOB`          | `@db.MediumBlob`               |
| `BIT`                 | `@db.Bit`                      |

#### MongoDB

`BinData`

| Native database type attribute | Notes                                                                             |
| :----------------------------- | :-------------------------------------------------------------------------------- |
| `@db.ObjectId`                 | Required if the underlying BSON type is `OBJECT_ID` (ID fields, relation scalars) |
| `@db.BinData`                  |                                                                                   |

#### Microsoft SQL Server

| Native database types | Native database type attribute | Notes |
| --------------------- | ------------------------------ | ----- |
| `binary`              | `@db.Binary`                   |
| `varbinary`           | `@db.VarBinary`                |       |
| `image`               | `@db.Image`                    |

#### SQLite

`BLOB`

#### CockroachDB

| Native database types        | Native database type attribute |
| ---------------------------- | ------------------------------ |
| `BYTES` \| `BYTEA` \| `BLOB` | `@db.Bytes`                    |

#### Clients

| Client                                                                                            | Type                                                                                                        | Description                                                                                            |
| :------------------------------------------------------------------------------------------------ | :---------------------------------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------- |
| Prisma Client JS                                                                                  | [`Uint8Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) | See [examples of working with `Bytes`](/orm/prisma-client/special-fields-and-types#working-with-bytes) |
| Prisma Client JS ([before v6](/orm/more/upgrade-guides/upgrading-versions/upgrading-to-prisma-6)) | [`Buffer`](https://nodejs.org/api/buffer.html)                                                              | See [examples of working with `Bytes`](/orm/prisma-client/special-fields-and-types#working-with-bytes) |

### `Unsupported`

:::warning

**Not supported by MongoDB** <br />
The [MongoDB connector](/orm/overview/databases/mongodb) does not support the `Unsupported` type.

:::

The `Unsupported` type was introduced in [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and allows you to represent data types in the Prisma schema that are not supported by Prisma Client. Fields of type `Unsupported` can be created during Introspection with `prisma db pull` or written by hand, and created in the database with Prisma Migrate or `db push`.

#### Remarks

- Fields with `Unsupported` types are not available in the generated client.
- If a model contains a **required** `Unsupported` type, `prisma.model.create(..)`, `prisma.model.update(...)` and `prisma.model.upsert(...)` are not available in Prisma Client.
- When you introspect a database that contains unsupported types, Prisma ORM will provide the following warning:

  ```
  *** WARNING ***

  These fields are not supported by Prisma Client, because Prisma does not currently support their types.
  * Model "Post", field: "circle", original data type: "circle"
  ```

#### Examples

```prisma
model Star {
  id       Int                    @id @default(autoincrement())
  position Unsupported("circle")?
  example1 Unsupported("circle")
  circle   Unsupported("circle")? @default(dbgenerated("'<(10,4),11>'::circle"))
}
```

## `model` field type modifiers

### `[]` modifier

Makes a field a list.

#### Remarks

- Cannot be optional (for example `Post[]?`).

##### Relational databases

- Scalar lists (arrays) are only supported in the data model if your database natively supports them. Currently, scalar lists are therefore only supported when using PostgreSQL or CockroachDB (since MySQL and SQLite don't natively support scalar lists).

##### MongoDB

- Scalar lists are supported

#### Examples

##### Define a scalar list

<TabbedContent code>
<TabItem value="Relational databases">

```prisma highlight=3;normal
model User {
  id             Int      @id @default(autoincrement())
  //highlight-next-line
  favoriteColors String[]
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma highlight=3;normal
model User {
  id             String   @id @default(auto()) @map("_id") @db.ObjectId
  //highlight-next-line
  favoriteColors String[]
}
```

</TabItem>
</TabbedContent>

##### Define a scalar list with a default value

Available in version 4.0.0 and later.

<TabbedContent code>
<TabItem value="Relational databases">

```prisma highlight=3;normal
model User {
  id             Int      @id @default(autoincrement())
  //highlight-next-line
  favoriteColors String[] @default(["red", "blue", "green"])
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma highlight=3;normal
model User {
  id             String   @id @default(auto()) @map("_id") @db.ObjectId
  //highlight-next-line
  favoriteColors String[] @default(["red", "blue", "green"])
}
```

</TabItem>
</TabbedContent>

### `?` modifier

Makes a field optional.

#### Remarks

- Cannot be used with a list field (for example, `Posts[]`)

#### Examples

##### Optional `name` field

```prisma highlight=3;normal
model User {
  id   Int     @id @default(autoincrement())
  //highlight-next-line
  name String?
}
```

## Attributes

Attributes modify the behavior of a [field](#model-fields) or block (e.g. [models](#model)). There are two ways to add attributes to your data model:

- _Field_ attributes are prefixed with `@`
- _Block_ attributes are prefixed with `@@`

Some attributes take arguments. Arguments in attributes are always named, but in most cases the argument _name_ can be omitted.

> **Note**: The leading underscore in a signature means the _argument name_ can be omitted.

### `@id`

Defines a single-field ID on the model.

#### Remarks

##### General

- Cannot be defined on a relation field
- Cannot be optional

##### Relational databases

- Corresponding database construct: `PRIMARY KEY`
- Can be annotated with a [`@default`](#default) attribute that uses [functions](#attribute-functions) to auto-generate an ID:

  - [`autoincrement()`](#autoincrement)
  - [`cuid()`](#cuid)
  - [`uuid()`](#uuid)
  - [`ulid()`](#ulid)

- Can be defined on any scalar field (`String`, `Int`, `enum`)

##### MongoDB

- Corresponding database construct: [Any valid BSON type, except arrays](https://www.mongodb.com/docs/manual/core/document/#the-_id-field)
- Every model must define an `@id` field
- The [underlying ID field name is always `_id`](https://www.mongodb.com/docs/manual/core/document/#the-_id-field), and must be mapped with `@map("_id")`
- Can be defined on any scalar field (`String`, `Int`, `enum`) unless you want to use `ObjectId` in your database
- To use an [`ObjectId`](https://www.mongodb.com/docs/manual/reference/method/ObjectId/) as your ID, you must:

  - Use the `String` or `Bytes` field type
  - Annotate your field with `@db.ObjectId`:

    ```prisma
    id   String  @db.ObjectId  @map("_id")
    ```

  - Optionally, annotate your field with a [`@default`](#default) attribute that uses [the `auto()` function](#auto) to auto-generate an `ObjectId`

    ```prisma
    id   String  @db.ObjectId  @map("_id") @default(auto())
    ```

- [`cuid()`](#cuid), [`uuid()`](#uuid) and [`ulid()`](#ulid) are supported but do not generate a valid `ObjectId` - use `auto()` instead for `@id`
- `autoincrement()` is **not supported**

#### Arguments

| Name        | Required | Type      | Description                                                                                                                                                                                                                                                    |
| ----------- | -------- | --------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `map`       | **No**   | `String`  | The name of the underlying primary key constraint in the database.<br /><br /> Not supported for MySQL or MongoDB.                                                                                                                                             |
| `length`    | **No**   | `number`  | Allows you to specify a maximum length for the subpart of the value to be indexed.<br /><br />MySQL only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                                     |
| `sort`      | **No**   | `String`  | Allows you to specify in what order the entries of the ID are stored in the database. The available options are `Asc` and `Desc`.<br /><br />SQL Server only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later. |
| `clustered` | **No**   | `Boolean` | Defines whether the ID is clustered or non-clustered. Defaults to `true`. <br /><br />SQL Server only. In preview in versions 3.13.0 and later, and in general availability in versions 4.0.0 and later.                                                       |

#### Signature

```prisma no-lines
@id(map: String?, length: number?, sort: String?, clustered: Boolean?)
```

> **Note**: Before version 4.0.0, or 3.5.0 with the `extendedIndexes` Preview feature enabled, the signature was:
>
> ```prisma no-lines
> @id(map: String?)
> ```

> **Note**: Before version 3.0.0, the signature was:
>
> ```prisma no-lines
> @id
> ```

#### Examples

In most cases, you want your database to create the ID. To do this, annotate the ID field with the `@default` attribute and initialize the field with a [function](#attribute-functions).

##### Generate autoincrementing integers as IDs (Relational databases only)

```prisma
model User {
  id   Int    @id @default(autoincrement())
  name String
}
```

##### Generate `ObjectId` as IDs (MongoDB only)

```prisma
model User {
  id   String @id @default(auto()) @map("_id") @db.ObjectId
  name String
}
```

##### Generate `cuid()` values as IDs

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(cuid())
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(cuid()) @map("_id")
  name String
}
```

:::warning

You cannot use `cuid()` to generate a default value if your `id` field is of type `ObjectId`. Use the following syntax to generate a valid `ObjectId`:

```prisma
id    String  @id @default(auto()) @db.ObjectId @map("_id")
```

:::

</TabItem>
</TabbedContent>

##### Generate `uuid()` values as IDs

<TabbedContent code>

<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(uuid())
  name String
}
```

</TabItem>

<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(uuid()) @map("_id")
  name String
}
```

:::warning

You cannot use `uuid()` to generate a default value if your `id` field is of type `ObjectId`. Use the following syntax to generate a valid `ObjectId`:

```prisma
id    String  @id @default(auto()) @db.ObjectId @map("_id")
```

:::
</TabItem>

</TabbedContent>

##### Generate `ulid()` values as IDs

<TabbedContent code>

<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(ulid())
  name String
}
```

</TabItem>

<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(ulid()) @map("_id")
  name String
}
```

:::warning

You cannot use `ulid()` to generate a default value if your `id` field is of type `ObjectId`. Use the following syntax to generate a valid `ObjectId`:

```prisma
id    String  @id @default(auto()) @db.ObjectId @map("_id")
```

:::
</TabItem>

</TabbedContent>

##### Single-field IDs _without_ default values

In the following example, `id` does not have a default value:

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
id    String   @id  @map("_id") @db.ObjectId
name  String
}
```

```prisma
model User {
id    String   @id  @map("_id")
name  String
}
```

</TabItem>
</TabbedContent>

Note that in the above case, you _must_ provide your own ID values when creating new records for the `User` model using Prisma Client, e.g.:

```ts
const newUser = await prisma.user.create({
  data: {
    id: 1,
    name: "Alice",
  },
});
```

###### Specify an ID on relation scalar field without a default value

In the following example, `authorId` is a both a relation scalar and the ID of `Profile`:

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model Profile {
  authorId Int    @id
  author   User   @relation(fields: [authorId], references: [id])
  bio      String
}

model User {
  id      Int      @id
  email   String   @unique
  name    String?
  profile Profile?
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model Profile {
  authorId String @id @map("_id") @db.ObjectId
  author   User   @relation(fields: [authorId], references: [id])
  bio      String
}

model User {
  id      String   @id @map("_id") @db.ObjectId
  email   String   @unique
  name    String?
  profile Profile?
}
```

</TabItem>
</TabbedContent>

In this scenario, you cannot create a `Profile` only - you must use Prisma Client's [nested writes](/orm/prisma-client/queries/relation-queries#nested-writes) create a `User` **or** connect the profile to an existing user.

The following example creates a user and a profile:

```ts
const userWithProfile = await prisma.user.create({
  data: {
    id: 3,
    email: "bob@prisma.io",
    name: "Bob Prismo",
    profile: {
      create: {
        bio: "Hello, I'm Bob Prismo and I love apples, blue nail varnish, and the sound of buzzing mosquitoes.",
      },
    },
  },
});
```

The following example connects a new profile to a user:

```ts
const profileWithUser = await prisma.profile.create({
  data: {
    bio: "Hello, I'm Bob and I like nothing at all. Just nothing.",
    author: {
      connect: {
        id: 22,
      },
    },
  },
});
```

### `@@id`

:::warning

**Not supported by MongoDB** <br />
The [MongoDB connector](/orm/overview/databases/mongodb) does not support composite IDs.

:::

Defines a multi-field ID (composite ID) on the model.

#### Remarks

- Corresponding database type: `PRIMARY KEY`
- Can be annotated with a [`@default`](#default) attribute that uses [functions](#attribute-functions) to auto-generate an ID
- Cannot be optional
- Can be defined on any scalar field (`String`, `Int`, `enum`)
- Cannot be defined on a relation field
- The name of the composite ID field in Prisma Client has the following pattern: `field1_field2_field3`

#### Arguments

| Name        | Required | Type               | Description                                                                                                                                                                                                                                                    |
| ----------- | -------- | ------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `fields`    | **Yes**  | `FieldReference[]` | A list of field names - for example, `["firstname", "lastname"]`                                                                                                                                                                                               |
| `name`      | **No**   | `String`           | The name that Prisma Client will expose for the argument covering all fields, e.g. `fullName` in `fullName: { firstName: "First", lastName: "Last"}`                                                                                                           |
| `map`       | **No**   | `String`           | The name of the underlying primary key constraint in the database.<br /><br />Not supported for MySQL.                                                                                                                                                         |
| `length`    | **No**   | `number`           | Allows you to specify a maximum length for the subpart of the value to be indexed.<br /><br />MySQL only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                                     |
| `sort`      | **No**   | `String`           | Allows you to specify in what order the entries of the ID are stored in the database. The available options are `Asc` and `Desc`.<br /><br />SQL Server only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later. |
| `clustered` | **No**   | `Boolean`          | Defines whether the ID is clustered or non-clustered. Defaults to `true`.<br /><br />SQL Server only. In preview in versions 3.13.0 and later, and in general availability in versions 4.0.0 and later.                                                        |

The name of the `fields` argument on the `@@id` attribute can be omitted:

```prisma no-lines
@@id(fields: [title, author])
@@id([title, author])
```

#### Signature

```prisma no-lines
@@id(_ fields: FieldReference[], name: String?, map: String?)
```

> **Note**: Until version 3.0.0, the signature was:
>
> ```prisma no-lines
> @@id(_ fields: FieldReference[])
> ```

#### Examples

##### Specify a multi-field ID on two `String` fields (Relational databases only)

```prisma
model User {
  firstName String
  lastName  String
  email     String  @unique
  isAdmin   Boolean @default(false)

  @@id([firstName, lastName])
}
```

When you create a user, you must provide a unique combination of `firstName` and `lastName`:

```ts
const user = await prisma.user.create({
  data: {
    firstName: "Alice",
    lastName: "Smith",
  },
});
```

To retrieve a user, use the generated composite ID field (`firstName_lastName`):

```ts
const user = await prisma.user.findUnique({
  where: {
    firstName_lastName: {
      firstName: "Alice",
      lastName: "Smith",
    },
  },
});
```

##### Specify a multi-field ID on two `String` fields and one `Boolean` field (Relational databases only)

```prisma
model User {
  firstName String
  lastName  String
  email     String  @unique
  isAdmin   Boolean @default(false)

  @@id([firstName, lastName, isAdmin])
}
```

When creating new `User` records, you now must provide a unique combination of values for `firstName`, `lastName` and `isAdmin`:

```ts
const user = await prisma.user.create({
  data: {
    firstName: "Alice",
    lastName: "Smith",
    isAdmin: true,
  },
});
```

##### Specify a multi-field ID that includes a relation field (Relational databases only)

```prisma
model Post {
  title     String
  published Boolean @default(false)
  author    User    @relation(fields: [authorId], references: [id])
  authorId  Int

  @@id([authorId, title])
}

model User {
  id    Int     @default(autoincrement())
  email String  @unique
  name  String?
  posts Post[]
}
```

When creating new `Post` records, you now must provide a unique combination of values for `authorId` (foreign key) and `title`:

```ts
const post = await prisma.post.create({
  data: {
    title: "Hello World",
    author: {
      connect: {
        email: "alice@prisma.io",
      },
    },
  },
});
```

### `@default`

Defines a [default value for a field](/orm/prisma-schema/data-model/models#defining-a-default-value).

#### Remarks

- Default values that cannot yet be represented in the Prisma schema are represented by the [`dbgenerated()` function](#dbgenerated) when you use [introspection](/orm/prisma-schema/introspection).
- Default values are not allowed on relation fields in the Prisma schema. Note however that you can still define default values on the fields backing a relation (the ones listed in the `fields` argument in the `@relation` attribute). A default value on the field backing a relation will mean that relation is populated automatically for you.
- Default values can be used with [scalar lists](/orm/prisma-client/special-fields-and-types/working-with-scalar-lists-arrays) in databases that natively support them.

##### Relational databases

- Corresponding database construct: `DEFAULT`
- Default values can be a static value (`4`, `"hello"`) or one of the following [functions](#attribute-functions):
  - [`autoincrement()`](#autoincrement)
  - [`sequence()`](#sequence) (CockroachDB only)
  - [`dbgenerated(...)`](#dbgenerated)
  - [`cuid()`](#cuid)
  - [`cuid(2)`](#cuid)
  - [`uuid()`](#uuid)
  - [`uuid(4)`](#uuid)
  - [`uuid(7)`](#uuid)
  - [`ulid()`](#ulid)
  - [`nanoid()`](#nanoid)
  - [`now()`](#now)
- Default values that cannot yet be represented in the Prisma schema are represented by the [`dbgenerated(...)` function](#dbgenerated) when you use [introspection](/orm/prisma-schema/introspection).
- Default values are not allowed on relation fields in the Prisma schema. Note however that you can still define default values on the fields backing a relation (the ones listed in the `fields` argument in the `@relation` attribute). A default value on the field backing a relation will mean that relation is populated automatically for you.
- Default values can be used with [scalar lists](/orm/prisma-client/special-fields-and-types/working-with-scalar-lists-arrays) in databases that natively support them.
- JSON data. Note that JSON needs to be enclosed with double-quotes inside the `@default` attribute, e.g.: `@default("[]")`. If you want to provide a JSON object, you need to enclose it with double-quotes and then escape any internal double quotes using a backslash, e.g.: `@default("{ \"hello\": \"world\" }")`.

##### MongoDB

- Default values can be a static value (`4`, `"hello"`) or one of the following [functions](#attribute-functions):
  - [`auto()`](#auto) (can only be used with `@db.ObjectId` to generate an `ObjectId` in MongoDB)
  - [`cuid()`](#cuid)
  - [`uuid()`](#uuid)
  - [`ulid()`](#ulid)
  - [`now()`](#now)

#### Arguments

| Name    | Required | Type                                      | Description          |
| ------- | -------- | ----------------------------------------- | -------------------- |
| `value` | **Yes**  | An expression (e.g. `5`, `true`, `now()`) |                      |
| `map`   | **No**   | String                                    | **SQL Server only.** |

The name of the `value` argument on the `@default` attribute can be omitted:

```prisma no-lines
id Int @id @default(value: autoincrement())
id Int @id @default(autoincrement())
```

#### Signature

```prisma no-lines
@default(_ value: Expression, map: String?)
```

> **Note**: Until version 3.0.0, the signature was:
>
> ```prisma no-lines
> @default(_ value: Expression)
> ```

#### Examples

##### Default value for an `Int`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email        String @unique
  profileViews Int    @default(0)
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id           String @default(auto()) @map("_id") @db.ObjectId
  profileViews Int    @default(0)
}
```

</TabItem>
</TabbedContent>

##### Default value for a `Float`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email  String @unique
  number Float  @default(1.1)
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id     String @default(auto()) @map("_id") @db.ObjectId
  number Float  @default(1.1)
}
```

</TabItem>
</TabbedContent>

##### Default value for `Decimal`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email  String  @unique
  number Decimal @default(22.99)
}
```

</TabItem>
<TabItem value="MongoDB" className="empty-code-tab">

[Not supported](https://github.com/prisma/prisma/issues/12637).

</TabItem>
</TabbedContent>

##### Default value for `BigInt`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email  String @unique
  number BigInt @default(34534535435353)
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id     String @default(auto()) @map("_id") @db.ObjectId
  number BigInt @default(34534535435353)
}
```

</TabItem>
</TabbedContent>

##### Default value for a `String`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email String @unique
  name  String @default("")
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @default(auto()) @map("_id") @db.ObjectId
  name String @default("")
}
```

</TabItem>
</TabbedContent>

##### Default value for a `Boolean`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email   String  @unique
  isAdmin Boolean @default(false)
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id      String  @default(auto()) @map("_id") @db.ObjectId
  isAdmin Boolean @default(false)
}
```

</TabItem>
</TabbedContent>

##### Default value for a `DateTime`

Note that static default values for `DateTime` are based on the [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) standard.

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email String   @unique
  data  DateTime @default("2020-03-19T14:21:00+02:00")
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String   @default(auto()) @map("_id") @db.ObjectId
  data DateTime @default("2020-03-19T14:21:00+02:00")
}
```

</TabItem>
</TabbedContent>

##### Default value for a `Bytes`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email  String @unique
  secret Bytes  @default("SGVsbG8gd29ybGQ=")
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id     String @default(auto()) @map("_id") @db.ObjectId
  secret Bytes  @default("SGVsbG8gd29ybGQ=")
}
```

</TabItem>
</TabbedContent>

##### Default value for an `enum`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
enum Role {
  USER
  ADMIN
}
```

```prisma highlight=5;normal
model User {
  id      Int      @id @default(autoincrement())
  email   String   @unique
  name    String?
  //highlight-next-line
  role    Role     @default(USER)
  posts   Post[]
  profile Profile?
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
enum Role {
  USER
  ADMIN
}
```

```prisma highlight=5;normal
model User {
  id      String   @id @default(auto()) @map("_id") @db.ObjectId
  email   String   @unique
  name    String?
  //highlight-next-line
  role    Role     @default(USER)
  posts   Post[]
  profile Profile?
}
```

</TabItem>
</TabbedContent>

##### Default values for scalar lists

<TabbedContent code>
<TabItem value="Relational databases">

```prisma highlight=4;normal
model User {
  id             Int      @id @default(autoincrement())
  posts          Post[]
  //highlight-next-line
  favoriteColors String[] @default(["red", "yellow", "purple"])
  roles          Role[]   @default([USER, DEVELOPER])
}

enum Role {
  USER
  DEVELOPER
  ADMIN
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma highlight=4;normal
model User {
  id             String   @id @default(auto()) @map("_id") @db.ObjectId
  posts          Post[]
  //highlight-next-line
  favoriteColors String[] @default(["red", "yellow", "purple"])
  roles          Role[]   @default([USER, DEVELOPER])
}

enum Role {
  USER
  DEVELOPER
  ADMIN
}
```

</TabItem>
</TabbedContent>

### `@unique`

Defines a unique constraint for this field.

#### Remarks

##### General

- A field annotated with `@unique` can be optional or required
- A field annotated with `@unique` _must_ be required if it represents the only unique constraint on a model without an `@id` / `@@id`
- A model can have any number of unique constraints
- Can be defined on any scalar field
- **Cannot** be defined on a relation field

##### Relational databases

- Corresponding database construct: `UNIQUE`
- `NULL` values are considered to be distinct (multiple rows with `NULL` values in the same column are allowed)
- Adding a unique constraint automatically adds a corresponding _unique index_ to the specified column(s).

##### MongoDB

- Enforced by a [unique index in MongoDB](https://www.mongodb.com/docs/manual/core/index-unique/)

#### Arguments

| Name        | Required | Type      | Description                                                                                                                                                                                                                                           |
| ----------- | -------- | --------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `map`       | **No**   | `String`  |                                                                                                                                                                                                                                                       |
| `length`    | **No**   | `number`  | Allows you to specify a maximum length for the subpart of the value to be indexed.<br /><br />MySQL only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                            |
| `sort`      | **No**   | `String`  | Allows you to specify in what order the entries of the constraint are stored in the database. The available options are `Asc` and `Desc`.<br /><br />In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later. |
| `clustered` | **No**   | `Boolean` | Defines whether the constraint is clustered or non-clustered. Defaults to `false`.<br /><br />SQL Server only. In preview in versions 3.13.0 and later, and in general availability in versions 4.0.0 and later.                                      |

- ¹ Can be required by some of the index and field types.

#### Signature

```prisma no-lines
@unique(map: String?, length: number?, sort: String?)
```

> **Note**: Before version 4.0.0, or 3.5.0 with the `extendedIndexes` Preview feature enabled, the signature was:
>
> ```prisma no-lines
> @unique(map: String?)
> ```

> **Note**: Before version 3.0.0, the signature was:
>
> ```no-lines
> @unique
> ```

#### Examples

##### Specify a unique attribute on a required `String` field

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  email String @unique
  name  String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @default(auto()) @map("_id") @db.ObjectId
  name String
}
```

</TabItem>
</TabbedContent>

##### Specify a unique attribute on an optional `String` field

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id    Int     @id @default(autoincrement())
  email String? @unique
  name  String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id    String  @id @default(auto()) @map("_id") @db.ObjectId
  email String? @unique
  name  String
}
```

</TabItem>
</TabbedContent>

##### Specify a unique attribute on relation scalar field `authorId`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model Post {
  author    User    @relation(fields: [authorId], references: [id])
  authorId  Int     @unique
  title     String
  published Boolean @default(false)
}

model User {
  id    Int     @id @default(autoincrement())
  email String? @unique
  name  String
  Post  Post[]
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model Post {
  author    User    @relation(fields: [authorId], references: [id])
  authorId  String  @unique @db.ObjectId
  title     String
  published Boolean @default(false)
}

model User {
  id    String  @id @default(auto()) @map("_id") @db.ObjectId
  email String? @unique
  name  String
  Post  Post[]
}
```

</TabItem>
</TabbedContent>

##### Specify a unique attribute with `cuid()` values as default values

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  token String @unique @default(cuid())
  name  String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id    String @id @default(auto()) @map("_id") @db.ObjectId
  token String @unique @default(cuid())
  name  String
}
```

</TabItem>
</TabbedContent>

### `@@unique`

Defines a compound [unique constraint](/orm/prisma-schema/data-model/models#defining-a-unique-field) for the specified fields.

#### Remarks

##### General

- All fields that make up the unique constraint **must** be mandatory fields. The following model is **not** valid because `id` could be `null`:

  ```prisma
  model User {
    firstname Int
    lastname  Int
    id        Int?

    @@unique([firstname, lastname, id])
  }
  ```

  The reason for this behavior is that all connectors consider `null` values to be distinct, which means that two rows that _look_ identical are considered unique:

  ```
   firstname  | lastname | id
   -----------+----------+------
   John       | Smith    | null
   John       | Smith    | null
  ```

- A model can have any number of `@@unique` blocks

##### Relational databases

- Corresponding database construct: `UNIQUE`
- A `@@unique` block is required if it represents the only unique constraint on a model without an `@id` / `@@id`
- Adding a unique constraint automatically adds a corresponding _unique index_ to the specified column(s)

##### MongoDB

- Enforced by a [compound index in MongoDB](https://www.mongodb.com/docs/manual/core/index-compound/)
- A `@@unique` block cannot be used as the only unique identifier for a model - MongoDB requires an `@id` field

#### Arguments

| Name        | Required | Type               | Description                                                                                                                                                                                                                                           |
| ----------- | -------- | ------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `fields`    | **Yes**  | `FieldReference[]` | A list of field names - for example, `["firstname", "lastname"]`. Fields must be mandatory - see remarks.                                                                                                                                             |
| `name`      | **No**   | `String`           | The name of the unique combination of fields - defaults to `fieldName1_fieldName2_fieldName3`                                                                                                                                                         |
| `map`       | **No**   | `String`           |                                                                                                                                                                                                                                                       |
| `length`    | **No**   | `number`           | Allows you to specify a maximum length for the subpart of the value to be indexed.<br /><br />MySQL only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                            |
| `sort`      | **No**   | `String`           | Allows you to specify in what order the entries of the constraint are stored in the database. The available options are `Asc` and `Desc`.<br /><br />In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later. |
| `clustered` | **No**   | `Boolean`          | Defines whether the constraint is clustered or non-clustered. Defaults to `false`.<br /><br />SQL Server only. In preview in versions 3.13.0 and later, and in general availability in versions 4.0.0 and later.                                      |

The name of the `fields` argument on the `@@unique` attribute can be omitted:

```prisma no-lines
@@unique(fields: [title, author])
@@unique([title, author])
@@unique(fields: [title, author], name: "titleAuthor")
```

The `length` and `sort` arguments are added to the relevant field names:

```prisma no-lines
@@unique(fields: [title(length:10), author])
@@unique([title(sort: Desc), author(sort: Asc)])
```

#### Signature

> ```prisma no-lines
> @@unique(_ fields: FieldReference[], name: String?, map: String?)
> ```

> **Note**: Before version 4.0.0, or before version 3.5.0 with the `extendedIndexes` Preview feature enabled, the signature was:
>
> ```prisma no-lines
> @@unique(_ fields: FieldReference[], name: String?, map: String?)
> ```

> **Note**: Before version 3.0.0, the signature was:
>
> ```prisma no-lines
> @@unique(_ fields: FieldReference[], name: String?)
> ```

#### Examples

##### Specify a multi-field unique attribute on two `String` fields

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id        Int     @default(autoincrement())
  firstName String
  lastName  String
  isAdmin   Boolean @default(false)

  @@unique([firstName, lastName])
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id        String  @id @default(auto()) @map("_id") @db.ObjectId
  firstName String
  lastName  String
  isAdmin   Boolean @default(false)

  @@unique([firstName, lastName])
}
```

</TabItem>
</TabbedContent>

To retrieve a user, use the generated field name (`firstname_lastname`):

```ts highlight=3;normal
const user = await prisma.user.findUnique({
  where: {
    firstName_lastName: {
      firstName: "Alice",
      lastName: "Smith",
      isAdmin: true,
    },
  },
});
```

##### Specify a multi-field unique attribute on two `String` fields and one `Boolean` field

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id        Int     @default(autoincrement())
  firstName String
  lastName  String
  isAdmin   Boolean @default(false)

  @@unique([firstName, lastName, isAdmin])
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id        String  @id @default(auto()) @map("_id") @db.ObjectId
  firstName String
  lastName  String
  isAdmin   Boolean @default(false)

  @@unique([firstName, lastName, isAdmin])
}
```

</TabItem>
</TabbedContent>

##### Specify a multi-field unique attribute that includes a relation field

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model Post {
  id        Int     @default(autoincrement())
  author    User    @relation(fields: [authorId], references: [id])
  authorId  Int
  title     String
  published Boolean @default(false)

  @@unique([authorId, title])
}

model User {
  id    Int    @id @default(autoincrement())
  email String @unique
  posts Post[]
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model Post {
  id        String  @id @default(auto()) @map("_id") @db.ObjectId
  author    User    @relation(fields: [authorId], references: [id])
  authorId  String  @db.ObjectId
  title     String
  published Boolean @default(false)

  @@unique([authorId, title])
}

model User {
  id    String @id @default(auto()) @map("_id") @db.ObjectId
  email String @unique
  posts Post[]
}
```

</TabItem>
</TabbedContent>

##### Specify a custom `name` for a multi-field unique attribute

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id        Int     @default(autoincrement())
  firstName String
  lastName  String
  isAdmin   Boolean @default(false)

  @@unique(fields: [firstName, lastName, isAdmin], name: "admin_identifier")
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id        String  @id @default(auto()) @map("_id") @db.ObjectId
  firstName String
  lastName  String
  isAdmin   Boolean @default(false)

  @@unique(fields: [firstName, lastName, isAdmin], name: "admin_identifier")
}
```

</TabItem>
</TabbedContent>

To retrieve a user, use the custom field name (`admin_identifier`):

```ts highlight=3;normal
const user = await prisma.user.findUnique({
  where: {
    admin_identifier: {
      firstName: "Alice",
      lastName: "Smith",
      isAdmin: true,
    },
  },
});
```

### `@@index`

Defines an index in the database.

#### Remarks

##### Relational databases

- Corresponding database construct: `INDEX`
- There are some additional index configuration options that cannot be provided via the Prisma schema yet. These include:
  - PostgreSQL and CockroachDB:
    - Define index fields as expressions (e.g. `CREATE INDEX title ON public."Post"((lower(title)) text_ops);`)
    - Define partial indexes with `WHERE`
    - Create indexes concurrently with `CONCURRENTLY`

:::info

While you cannot configure these option in your Prisma schema, you can still configure them on the database-level directly.

:::

##### MongoDB

- In version `3.12.0` and later, you can define an index on a field of a [composite type](/orm/prisma-schema/data-model/models#defining-composite-types) using the syntax `@@index([compositeType.field])`. See [Defining composite type indexes](/orm/prisma-schema/data-model/models#defining-composite-type-indexes) for more details.

#### Arguments

| Name        | Required | Type                         | Description                                                                                                                                                                                                                                                                                                              |
| ----------- | -------- | ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `fields`    | **Yes**  | `FieldReference[]`           | A list of field names - for example, `["firstname", "lastname"]`                                                                                                                                                                                                                                                         |
| `name`      | **No**   | `String`                     | The name that Prisma Client will expose for the argument covering all fields, e.g. `fullName` in `fullName: { firstName: "First", lastName: "Last"}`                                                                                                                                                                     |
| `map`       | **No**   | `map`                        | The name of the index in the underlying database (Prisma generates an index name that respects identifier length limits if you do not specify a name. Prisma uses the following naming convention: `tablename.field1_field2_field3_unique`)                                                                              |
| `length`    | **No**   | `number`                     | Allows you to specify a maximum length for the subpart of the value to be indexed.<br /><br />MySQL only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                                                                                               |
| `sort`      | **No**   | `String`                     | Allows you to specify in what order the entries of the index or constraint are stored in the database. The available options are `asc` and `desc`.<br /><br />In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                                           |
| `clustered` | **No**   | `Boolean`                    | Defines whether the index is clustered or non-clustered. Defaults to `false`.<br /><br />SQL Server only. In preview in versions 3.5.0 and later, and in general availability in versions 4.0.0 and later.                                                                                                               |
| `type`      | **No**   | `identifier`                 | Allows you to specify an index access method. Defaults to `BTree`.<br /><br />PostgreSQL and CockroachDB only. In preview with the `Hash` index access method in versions 3.6.0 and later, and with the `Gist`, `Gin`, `SpGist` and `Brin` methods added in 3.14.0. In general availability in versions 4.0.0 and later. |
| `ops`       | **No**   | `identifier` or a `function` | Allows you to define the index operators for certain index types.<br /><br />PostgreSQL only. In preview in versions 3.14.0 and later, and in general availability in versions 4.0.0 and later.                                                                                                                          |

The _name_ of the `fields` argument on the `@@index` attribute can be omitted:

```prisma no-lines
@@index(fields: [title, author])
@@index([title, author])
```

The `length` and `sort` arguments are added to the relevant field names:

```prisma no-lines
@@index(fields: [title(length:10), author])
@@index([title(sort: Asc), author(sort: Desc)])
```

#### Signature

```prisma no-lines
@@index(_ fields: FieldReference[], map: String?)
```

> **Note**: Until version 3.0.0, the signature was:
>
> ```prisma no-lines
> @@index(_ fields: FieldReference[], name: String?)
> ```
>
> The old `name` argument will still be accepted to avoid a breaking change.

#### Examples

Assume you want to add an index for the `title` field of the `Post` model

##### Define a single-column index (Relational databases only)

```prisma
model Post {
  id      Int     @id @default(autoincrement())
  title   String
  content String?

  @@index([title])
}
```

##### Define a multi-column index (Relational databases only)

```prisma
model Post {
  id      Int     @id @default(autoincrement())
  title   String
  content String?

  @@index([title, content])
}
```

##### Define an index with a name (Relational databases only)

```prisma
model Post {
  id      Int     @id @default(autoincrement())
  title   String
  content String?

  @@index(fields: [title, content], name: "main_index")
}
```

##### Define an index on a composite type field (Relational databases only)

```prisma
type Address {
  street String
  number Int
}

model User {
  id      Int     @id
  email   String
  address Address

  @@index([address.number])
}
```

### `@relation`

Defines meta information about the relation. [Learn more](/orm/prisma-schema/data-model/relations#the-relation-attribute).

#### Remarks

##### Relational databases

- Corresponding database constructs: `FOREIGN KEY` / `REFERENCES`

##### MongoDB

- If your model's primary key is of type `ObjectId` in the underlying database, both the primary key _and_ the foreign key must have the `@db.ObjectId` attribute

#### Arguments

| Name         | Type                                                                                                                                           | Required                                                                                | Description                                                                                                                                                                | Example                                               |
| :----------- | :--------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------------------------------------------------- |
| `name`       | `String`                                                                                                                                       | Sometimes (e.g. to disambiguate a relation)                                             | Defines the name of the relationship. In an m-n-relation, it also determines the name of the underlying relation table.                                                    | `"CategoryOnPost"`, `"MyRelation"`                    |
| `fields`     | `FieldReference[]`                                                                                                                             | On [annotated](/orm/prisma-schema/data-model/relations#relation-fields) relation fields | A list of [fields](/orm/prisma-schema/data-model/models#defining-fields) of the _current_ model                                                                            | `["authorId"]`, `["authorFirstName, authorLastName"]` |
| `references` | `FieldReference[]`                                                                                                                             | On [annotated](/orm/prisma-schema/data-model/relations#relation-fields) relation fields | A list of [fields](/orm/prisma-schema/data-model/models#defining-fields) of the model on _the other side of the relation_                                                  | `["id"]`, `["firstName, lastName"]`                   |
| `map`        | `String`                                                                                                                                       | No                                                                                      | Defines a [custom name](/orm/prisma-schema/data-model/database-mapping#constraint-and-index-names) for the foreign key in the database.                                    | `["id"]`, `["firstName, lastName"]`                   |
| `onUpdate`   | Enum. See [Types of referential actions](/orm/prisma-schema/data-model/relations/referential-actions#types-of-referential-actions) for values. | No                                                                                      | Defines the [referential action](/orm/prisma-schema/data-model/relations/referential-actions) to perform when a referenced entry in the referenced model is being updated. | `Cascade`, `NoAction`                                 |
| `onDelete`   | Enum. See [Types of referential actions](/orm/prisma-schema/data-model/relations/referential-actions#types-of-referential-actions) for values. | No                                                                                      | Defines the [referential action](/orm/prisma-schema/data-model/relations/referential-actions) to perform when a referenced entry in the referenced model is being deleted. | `Cascade`, `NoAction`                                 |

The name of the `name` argument on the `@relation` attribute can be omitted (`references` is required):

```prisma
@relation(name: "UserOnPost", references: [id])
@relation("UserOnPost", references: [id])

// or

@relation(name: "UserOnPost")
@relation("UserOnPost")
```

#### Signature

```prisma no-lines
@relation(_ name: String?, fields: FieldReference[]?, references: FieldReference[]?, onDelete: ReferentialAction?, onUpdate: ReferentialAction?, map: String?)
```

With SQLite, the signature changes to:

```prisma no-lines
@relation(_ name: String?, fields: FieldReference[]?, references: FieldReference[]?, onDelete: ReferentialAction?, onUpdate: ReferentialAction?)
```

> **Note**: Until version 3.0.0, the signature was:
>
> ```prisma no-lines
> @relation(_ name: String?, fields: FieldReference[]?, references: FieldReference[]?)
> ```

#### Examples

See: [The `@relation` attribute](/orm/prisma-schema/data-model/relations#the-relation-attribute).

### `@map`

Maps a field name or enum value from the Prisma schema to a column or document field with a different name in the database. If you do not use `@map`, the Prisma field name matches the column name or document field name exactly.

> See [Using custom model and field names](/orm/prisma-client/setup-and-configuration/custom-model-and-field-names) to see how `@map` and `@@map` changes the generated Prisma Client.

#### Remarks

##### General

- `@map` **does not** rename the columns / fields in the database
- `@map` **does** [change the field names in the generated client](#map-the-firstname-field-to-a-column-called-first_name)

##### MongoDB

Your `@id` field must include `@map("_id")`. For example:

```prisma
model User {
  id String @default(auto()) @map("_id") @db.ObjectId
}
```

#### Arguments

| Name   | Type     | Required | Description                                                                  | Example                         |
| :----- | :------- | :------- | :--------------------------------------------------------------------------- | :------------------------------ |
| `name` | `String` | **Yes**  | The database column (relational databases) or document field (MongoDB) name. | `"comments"`, `"someFieldName"` |

The name of the `name` argument on the `@map` attribute can be omitted:

```prisma
@map(name: "is_admin")
@map("users")
```

#### Signature

```prisma no-lines
@map(_ name: String)
```

#### Examples

##### Map the `firstName` field to a column called `first_name`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id        Int    @id @default(autoincrement())
  firstName String @map("first_name")
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id        String @id @default(auto()) @map("_id") @db.ObjectId
  firstName String @map("first_name")
}
```

</TabItem>
</TabbedContent>

The generated client:

```ts highlight=3;normal
await prisma.user.create({
  data: {
    firstName: "Yewande", // first_name --> firstName
  },
});
```

##### Map an enum named `ADMIN` to a database enum named `admin`

```prisma
enum Role {
  ADMIN    @map("admin")
  CUSTOMER
}
```

### `@@map`

Maps the Prisma schema model name to a table (relational databases) or collection (MongoDB) with a different name, or an enum name to a different underlying enum in the database. If you do not use `@@map`, the model name matches the table (relational databases) or collection (MongoDB) name exactly.

> See [Using custom model and field names](/orm/prisma-client/setup-and-configuration/custom-model-and-field-names) to see how `@map` and `@@map` changes the generated Prisma Client.

#### Arguments

| Name   | Type     | Required | Description                                                             | Example                                     |
| :----- | :------- | :------- | :---------------------------------------------------------------------- | :------------------------------------------ |
| `name` | `String` | **Yes**  | The database table (relational databases) or collection (MongoDB) name. | `"comments"`, `"someTableOrCollectionName"` |

The name of the `name` argument on the `@@map` attribute can be omitted

```prisma
@@map(name: "users")
@@map("users")
```

#### Signature

```prisma no-lines
@@map(_ name: String)
```

#### Examples

##### Map the `User` model to a database table/collection named `users`

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   Int    @id @default(autoincrement())
  name String

  @@map("users")
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(auto()) @map("_id") @db.ObjectId
  name String

  @@map("users")
}
```

</TabItem>
</TabbedContent>

The generated client:

```ts highlight=1;normal
await prisma.user.create({
  // users --> user
  data: {
    name: "Yewande",
  },
});
```

##### Map the `Role` enum to a native enum in the database named `_Role` its values to lowercase values in the database

```prisma
enum Role {
  ADMIN    @map("admin")
  CUSTOMER @map("customer")

  @@map("_Role")
}
```

### `@updatedAt`

Automatically stores the time when a record was last updated. If you do not supply a time yourself, Prisma Client will automatically set the value for fields with this attribute.

#### Remarks

- Compatible with [`DateTime`](#datetime) fields
- Implemented at Prisma ORM level

:::warning

In versions before [4.4.0](https://github.com/prisma/prisma/releases/tag/4.4.0), if you're also using [`now()`](/orm/reference/prisma-schema-reference#now), the time might differ from the `@updatedAt` values if your database and app have different time zones. This happens because `@updatedAt` operates at the Prisma ORM level, while `now()` operates at the database level.

:::

:::note

If you pass an empty update clause, the @updatedAt value will remain unchanged. For example:

```ts
await prisma.user.update({
  where: {
    id: 1,
  },
  data: {}, //<- Empty update clause
});
```

:::

#### Arguments

N/A

#### Signature

```prisma no-lines
@updatedAt
```

#### Examples

<TabbedContent code>
<TabItem value="Relational databases">

```prisma line-number
model Post {
  id        String   @id
  updatedAt DateTime @updatedAt
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma line-number
model Post {
  id        String   @id @map("_id") @db.ObjectId
  updatedAt DateTime @updatedAt
}
```

</TabItem>
</TabbedContent>

### `@ignore`

Add `@ignore` to a field that you want to exclude from Prisma Client (for example, a field that you do not want Prisma Client users to update). Ignored fields are excluded from the generated Prisma Client. The model's `create` method is disabled when doing this for _required_ fields with no `@default` (because the database cannot create an entry without that data).

#### Remarks

- In [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and later, Prisma ORM automatically adds `@ignore` to fields that _refer to_ invalid models when you introspect.

#### Examples

The following example demonstrates manually adding `@ignore` to exclude the `email` field from Prisma Client:

```prisma file=schema.prisma highlight=4;normal
model User {
  id    Int    @id
  name  String
  //highlight-next-line
  email String @ignore // this field will be excluded
}
```

### `@@ignore`

Add `@@ignore` to a model that you want to exclude from Prisma Client (for example, a model that you do not want Prisma users to update). Ignored models are excluded from the generated Prisma Client.

#### Remarks

- In [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and later, Prisma ORM adds `@@ignore` to an invalid model. (It also adds [`@ignore`](#ignore) to relations pointing to such a model)

#### Examples

In the following example, the `Post` model is invalid because it does not have a unique identifier. Use `@@ignore` to exclude it from the generated Prisma Client API:

```prisma file=schema.prisma highlight=7;normal
/// The underlying table does not contain a valid unique identifier and can therefore currently not be handled by Prisma Client.
model Post {
  id       Int  @default(autoincrement()) // no unique identifier
  author   User @relation(fields: [authorId], references: [id])
  authorId Int

  //highlight-next-line
  @@ignore
}
```

In the following example, the `Post` model is invalid because it does not have a unique identifier, and the `posts` relation field on `User` is invalid because it refers to the invalid `Post` model. Use `@@ignore` on the `Post` model and `@ignore` on the `posts` relation field in `User` to exclude both the model and the relation field from the generated Prisma Client API:

```prisma file=schema.prisma highlight=7,13;normal
/// The underlying table does not contain a valid unique identifier and can therefore currently not be handled by Prisma Client.
model Post {
  id       Int  @default(autoincrement()) // no unique identifier
  author   User @relation(fields: [authorId], references: [id])
  authorId Int

  //highlight-next-line
  @@ignore
}

model User {
  id    Int     @id @default(autoincrement())
  name  String?
  //highlight-next-line
  posts Post[]  @ignore
}
```

### `@@schema`

Add `@@schema` to a model to specify which schema in your database should contain the table associated with that model. Learn more about [adding multiple schema's here](/orm/prisma-schema/data-model/multi-schema).

:::note

[Multiple database schema](/orm/prisma-schema/data-model/multi-schema) support is only available with the PostgreSQL, CockroachDB, and SQL Server connectors.

:::


#### Arguments

| Name   | Type     | Required | Description                      | Example            |
| :----- | :------- | :------- | :------------------------------- | :----------------- |
| `name` | `String` | **Yes**  | The name of the database schema. | `"base"`, `"auth"` |

The name of the `name` argument on the `@@schema` attribute can be omitted

```prisma
@@schema(name: "auth")
@@schema("auth")
```

#### Signature

```prisma no-lines
@@schema(_ name: String)
```

#### Examples

##### Map the `User` model to a database schema named `auth`

```prisma highlight=3,9,16;normal
generator client {
  provider        = "prisma-client"
  output          = "./generated"
}

datasource db {
  provider = "postgresql"
  //highlight-next-line
  schemas  = ["auth"]
}

model User {
  id   Int    @id @default(autoincrement())
  name String

  //highlight-next-line
  @@schema("auth")
}
```

:::info

For more information about using the `multiSchema` feature, refer to [this guide](/orm/prisma-schema/data-model/multi-schema).

:::

### `@shardKey`

:::note
This features requires the `shardKeys` Preview feature flag on your `generator`:
```prisma
generator client {
  provider = "prisma-client"
  output = "../generated/prisma"
  previewFeatures = ["shardKeys"]
}
```
:::


The `@shardKey` attribute is only compatible with [PlanetScale](http://planetscale.com/) databases. It enables you define a [shard key](https://planetscale.com/docs/vitess/sharding) on a field of your model:

```prisma
model User {
  id     String @default(uuid())
  region String @shardKey
}
```

### `@@shardKey`

:::note
This features requires the `shardKeys` Preview feature flag on your `generator`:
```prisma
generator client {
  provider = "prisma-client"
  output = "../generated/prisma"
  previewFeatures = ["shardKeys"]
}
```
:::

The `@shardKey` attribute is only compatible with [PlanetScale](http://planetscale.com/) databases. It enables you define a [shard key](https://planetscale.com/docs/vitess/sharding) on multiple fields of your model:

```prisma
model User {
  id         String @default(uuid())
  country    String
  customerId String
  @@shardKey([country, customerId])
}
```

## Attribute functions

### `auto()`

:::warning
This function is available on MongoDB only.
:::

Represents **default values** that are automatically generated by the database.

#### Remarks

##### MongoDB

Used to generate an `ObjectId` for `@id` fields:

```prisma
id  String  @map("_id") @db.ObjectId @default(auto())
```

##### Relational databases

The `auto()` function is not available on relational databases.

#### Example

##### Generate `ObjectId` (MongoDB only)

```prisma
model User {
  id   String  @id @default(auto()) @map("_id") @db.ObjectId
  name String?
}
```

### `autoincrement()`

:::warning

**Not supported by MongoDB** <br />
The [MongoDB connector](/orm/overview/databases/mongodb) does not support the `autoincrement()` function.

:::

Create a sequence of integers in the underlying database and assign the incremented values to the ID values of the created records based on the sequence.

#### Remarks

- Compatible with `Int` on most databases (`BigInt` on CockroachDB)
- Implemented on the database-level, meaning that it manifests in the database schema and can be recognized through introspection. Database implementations:

  | Database    | Implementation                                                                                    |
  | ----------- | ------------------------------------------------------------------------------------------------- |
  | PostgreSQL  | [`SERIAL`](https://www.postgresql.org/docs/9.1/datatype-numeric.html#DATATYPE-SERIAL) type        |
  | MySQL       | [`AUTO_INCREMENT`](https://dev.mysql.com/doc/refman/8.0/en/example-auto-increment.html) attribute |
  | SQLite      | [`AUTOINCREMENT`](https://www.sqlite.org/autoinc.html) keyword                                    |
  | CockroachDB | [`SERIAL`](https://www.postgresql.org/docs/9.1/datatype-numeric.html#DATATYPE-SERIAL) type        |

#### Examples

##### Generate autoincrementing integers as IDs (Relational databases only)

```prisma
model User {
  id   Int    @id @default(autoincrement())
  name String
}
```

### `sequence()`

:::info

**Only supported by CockroachDB** <br />
The sequence function is only supported by [CockroachDB connector](/orm/overview/databases/cockroachdb).

:::

Create a sequence of integers in the underlying database and assign the incremented values to the values of the created records based on the sequence.

#### Optional arguments

| Argument    | Example                                                                                                                                                                                                            |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `virtual`   | `@default(sequence(virtual))`<br />Virtual sequences are sequences that do not generate monotonically increasing values and instead produce values like those generated by the built-in function `unique_rowid()`. |
| `cache`     | `@default(sequence(cache: 20))`<br />The number of sequence values to cache in memory for reuse in the session. A cache size of `1` means that there is no cache, and cache sizes of less than `1` are not valid.  |
| `increment` | `@default(sequence(increment: 4))`<br />The new value by which the sequence is incremented. A negative number creates a descending sequence. A positive number creates an ascending sequence.                      |
| `minValue`  | `@default(sequence(minValue: 10))`<br />The new minimum value of the sequence.                                                                                                                                     |
| `maxValue`  | `@default(sequence(maxValue: 3030303))`<br />The new maximum value of the sequence.                                                                                                                                |
| `start`     | `@default(sequence(start: 2))`<br />The value the sequence starts at, if it's restarted or if the sequence hits the `maxValue`.                                                                                    |

#### Examples

##### Generate sequencing integers as IDs

```prisma
model User {
  id   Int    @id @default(sequence(maxValue: 4294967295))
  name String
}
```

### `cuid()`

Generate a globally unique identifier based on the [`cuid`](https://github.com/ericelliott/cuid) spec.

If you'd like to use [`cuid2`](https://github.com/paralleldrive/cuid2) values, you can pass `2` as an argument to the `cuid` function: `cuid(2)`.

#### Remarks

- Compatible with `String`.
- Implemented by Prisma ORM and therefore not "visible" in the underlying database schema. You can still use `cuid()` when using [introspection](/orm/prisma-schema/introspection) by [manually changing your Prisma schema](/orm/prisma-client/setup-and-configuration/custom-model-and-field-names) and [generating Prisma Client](/orm/prisma-client/setup-and-configuration/generating-prisma-client), in that case the values will be generated by Prisma's [query engine](/orm/more/under-the-hood/engines).
- Since the length of `cuid()` output is undefined per the cuid creator, a safe field size is 30 characters, in order to allow for enough characters for very large values. If you set the field size as less than 30, and then a larger value is generated by `cuid()`, you might see Prisma Client errors such as `Error: The provided value for the column is too long for the column's type.`
- For **MongoDB**: `cuid()` does not generate a valid `ObjectId`. You can use [`@db.ObjectId` syntax](#generate-objectid-as-ids-mongodb-only) if you want to use `ObjectId` in the underlying database. However, you can still use `cuid()` if your `_id` field is not of type `ObjectId`.

#### Examples

##### Generate `cuid()` values as IDs

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(cuid())
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(cuid()) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

##### Generate `cuid(2)` values as IDs based on the `cuid2` spec

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(cuid(2))
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(cuid(2)) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

### `uuid()`

Generate a globally unique identifier based on the [UUID](https://en.wikipedia.org/wiki/Universally_unique_identifier) spec. Prisma ORM supports versions 4 (default) and 7.

#### Remarks

- Compatible with `String`.
- Implemented by Prisma ORM and therefore not "visible" in the underlying database schema. You can still use `uuid()` when using [introspection](/orm/prisma-schema/introspection) by [manually changing your Prisma schema](/orm/prisma-client/setup-and-configuration/custom-model-and-field-names) and [generating Prisma Client](/orm/prisma-client/setup-and-configuration/generating-prisma-client), in that case the values will be generated by Prisma ORM's [query engine](/orm/more/under-the-hood/engines).
- For **relational databases**: If you do not want to use Prisma ORM's `uuid()` function, you can use [the native database function with `dbgenerated`](#override-default-value-behavior-for-supported-types).
- For **MongoDB**: `uuid()` does not generate a valid `ObjectId`. You can use [`@db.ObjectId` syntax](#generate-objectid-as-ids-mongodb-only) if you want to use `ObjectId` in the underlying database. However, you can still use `uuid()` if your `_id` field is not of type `ObjectId`.

#### Examples

##### Generate `uuid()` values as IDs using UUID v4

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(uuid())
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(uuid()) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

##### Generate `uuid(7)` values as IDs using UUID v7

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(uuid(7))
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(uuid(7)) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

### `ulid()`

Generate a universally unique lexicographically sortable identifier based on the [ULID](https://github.com/ulid/spec) spec.

#### Remarks

- `ulid()` will produce 128-bit random identifier represented as a 26-character long alphanumeric string, e.g.: `01ARZ3NDEKTSV4RRFFQ69G5FAV`

#### Examples

##### Generate `ulid()` values as IDs

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(ulid())
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(ulid()) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

### `nanoid()`

Generated values based on the [Nano ID](https://github.com/ai/nanoid) spec. `nanoid()` accepts an integer value between 2 and 255 that specifies the _length_ of the generate ID value, e.g. `nanoid(16)` will generated ID with 16 characters. If you don't provide a value to the nanoid() function, the default value is 21.

:::info

Nano ID is quite comparable to UUID v4 (random-based). It has a similar number of random bits in the ID (126 in Nano ID and 122 in UUID), so it has a similar collision probability:

For there to be a one in a billion chance of duplication, 103 trillion version 4 IDs must be generated.

There are two main differences between Nano ID and UUID v4:

- Nano ID uses a bigger alphabet, so a similar number of random bits are packed in just 21 symbols instead of 36.
- Nano ID code is 4 times smaller than uuid/v4 package: 130 bytes instead of 423.

:::

#### Remarks

- Compatible with `String`.
- Implemented by Prisma ORM and therefore not "visible" in the underlying database schema. You can still use `uuid()` when using [introspection](/orm/prisma-schema/introspection) by [manually changing your Prisma schema](/orm/prisma-client/setup-and-configuration/custom-model-and-field-names) and [generating Prisma Client](/orm/prisma-client/setup-and-configuration/generating-prisma-client), in that case the values will be generated by Prisma ORM's [query engine](/orm/more/under-the-hood/engines).
- For **MongoDB**: `nanoid()` does not generate a valid `ObjectId`. You can use [`@db.ObjectId` syntax](#generate-objectid-as-ids-mongodb-only) if you want to use `ObjectId` in the underlying database. However, you can still use `nanoid()` if your `_id` field is not of type `ObjectId`.

#### Examples

##### Generate `nanoid()` values with 21 characters as IDs

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(nanoid())
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(nanoid()) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

##### Generate `nanoid()` values with 16 characters as IDs

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id   String @id @default(nanoid(16))
  name String
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id   String @id @default(nanoid(16)) @map("_id")
  name String
}
```

</TabItem>
</TabbedContent>

### `now()`

Set a timestamp of the time when a record is created.

#### Remarks

##### General

- Compatible with [`DateTime`](#datetime)

:::warning

In versions before [4.4.0](https://github.com/prisma/prisma/releases/tag/4.4.0), if you're also using [`@updatedAt`](/orm/reference/prisma-schema-reference#updatedat), the time might differ from the `now()` values if your database and app have different time zones. This happens because `@updatedAt` operates at the Prisma ORM level, while `now()` operates at the database level.

:::

##### Relational databases

- Implemented on the database-level, meaning that it manifests in the database schema and can be recognized through introspection. Database implementations:

  | Database    | Implementation                                                                                                                                  |
  | ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
  | PostgreSQL  | [`CURRENT_TIMESTAMP`](https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-CURRENT) and aliases like `now()`      |
  | MySQL       | [`CURRENT_TIMESTAMP`](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_current-timestamp) and aliases like `now()` |
  | SQLite      | `CURRENT_TIMESTAMP` and aliases like `date('now')`                                                                                              |
  | CockroachDB | [`CURRENT_TIMESTAMP`](https://www.cockroachlabs.com/docs/stable/functions-and-operators#special-syntax-forms) and aliases like `now()`          |

##### MongoDB

- Implemented at Prisma ORM level

#### Examples

##### Set current timestamp value when a record is created

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
model User {
  id        String   @id
  createdAt DateTime @default(now())
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
model User {
  id        String   @id @default(auto()) @map("_id") @db.ObjectId
  createdAt DateTime @default(now())
}
```

</TabItem>
</TabbedContent>

### `dbgenerated(...)`

Represents **default values** that cannot be expressed in the Prisma schema (such as `random()`).

#### Remarks

##### Relational databases

- Compatible with any scalar type
- Can not be an empty string `dbgenerated("")` in [2.21.0](https://github.com/prisma/prisma/releases/tag/2.21.0) and later
- Accepts a `String` value in [2.17.0](https://github.com/prisma/prisma/releases/tag/2.17.0) and later, which allows you to:

  - [Set default values for `Unsupported` types](#set-default-value-for-unsupported-type)
  - [Override default value behavior for supported types](#override-default-value-behavior-for-supported-types)

- String values in `dbgenerated(...)` might not match what the DB returns as the default value, because values such as strings may be explicitly cast (e.g. `'hello'::STRING`). When a mismatch is present, Prisma Migrate indicates a migration is still needed. You can use `prisma db pull` to infer the correct value to resolve the discrepancy. ([Related issue](https://github.com/prisma/prisma/issues/14917))

#### Examples

##### Set default value for `Unsupported` type

```prisma
circle     Unsupported("circle")?   @default(dbgenerated("'<(10,4),11>'::circle"))
```

##### Override default value behavior for supported types

You can also use `dbgenerated(...)` to set the default value for supported types. For example, in PostgreSQL you can generate UUIDs at the database level rather than rely on Prisma ORM's `uuid()`:

```prisma highlight=2;add|3;delete
model User {
  //add-next-line
  id   String  @id @default(dbgenerated("gen_random_uuid()")) @db.Uuid
  //delete-next-line
  id   String  @id @default(uuid()) @db.Uuid
  test String?
}
```

:::info

[`gen_random_uuid()` is a PostgreSQL function](https://www.postgresql.org/docs/13/functions-uuid.html). To use it in PostgreSQL versions 12.13 and earlier, you must enable the `pgcrypto` extension.<br /><br />In Prisma ORM versions 4.5.0 and later, you can declare the `pgcrypto` extension in your Prisma schema with the [`postgresqlExtensions` preview feature](/orm/prisma-schema/postgresql-extensions).

:::

## Attribute argument types

### `FieldReference[]`

An array of [field](#model-fields) names: `[id]`, `[firstName, lastName]`

### `String`

A variable length text in double quotes: `""`, `"Hello World"`, `"Alice"`

### `Expression`

An expression that can be evaluated by Prisma ORM: `42.0`, `""`, `Bob`, `now()`, `cuid()`

## `enum`

:::warning

**Not supported Microsoft SQL Server** <br />
The [Microsoft SQL Server connector](/orm/overview/databases/sql-server) does not support the `enum` type.

:::

Defines an [enum](/orm/prisma-schema/data-model/models#defining-enums) .

### Remarks

- Enums are natively supported by [PostgreSQL](https://www.postgresql.org/docs/current/datatype-enum.html) and [MySQL](https://dev.mysql.com/doc/refman/8.0/en/enum.html)
- Enums are implemented and enforced at Prisma ORM level in SQLite and MongoDB

### Naming conventions

- Enum names must start with a letter (they are typically spelled in [PascalCase](http://wiki.c2.com/?PascalCase))
- Enums must use the singular form (e.g. `Role` instead of `role`, `roles` or `Roles`).
- Must adhere to the following regular expression: `[A-Za-z][A-Za-z0-9_]*`

### Examples

#### Specify an `enum` with two possible values

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
enum Role {
  USER
  ADMIN
}

model User {
  id   Int  @id @default(autoincrement())
  role Role
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
enum Role {
  USER
  ADMIN
}

model User {
  id   String @id @default(auto()) @map("_id") @db.ObjectId
  role Role
}
```

</TabItem>
</TabbedContent>

#### Specify an `enum` with two possible values and set a default value

<TabbedContent code>
<TabItem value="Relational databases">

```prisma
enum Role {
  USER
  ADMIN
}

model User {
  id   Int  @id @default(autoincrement())
  role Role @default(USER)
}
```

</TabItem>
<TabItem value="MongoDB">

```prisma
enum Role {
  USER
  ADMIN
}

model User {
  id   String @id @default(auto()) @map("_id") @db.ObjectId
  role Role   @default(USER)
}
```

</TabItem>
</TabbedContent>

## `type`

:::warning

Composite types are available **for MongoDB only**.

:::

:::info

Composite types are available in versions 3.12.0 and later, and in versions 3.10.0 and later if you enable the `mongodb` Preview feature flag.

:::

Defines a [composite type](/orm/prisma-schema/data-model/models#defining-composite-types) .

### Naming conventions

Type names must:

- start with a letter (they are typically spelled in [PascalCase](http://wiki.c2.com/?PascalCase))
- adhere to the following regular expression: `[A-Za-z][A-Za-z0-9_]*`

### Examples

#### Define a `Product` model with a list of `Photo` composite types

```prisma
model Product {
  id     String  @id @default(auto()) @map("_id") @db.ObjectId
  name   String
  photos Photo[]
}

type Photo {
  height Int
  width  Int
  url    String
}
```
